Effect And Mechanism Of Bifidobacterial Lipoteichoic Acid Protects Against Premature Senescence Induced By H₂O₂

ObjectiveBifidobacterium is an important normal physiological bacterium in human and animal colon. Lipoteichoic acid(LTA)of Bifidobacterium is able to against aging but the mechanism is still unclear.In order to explore the effect of Lipoteichoic acid (LTA) of Bifidobacterium protecting human WI-38 against cytotoxic dose of H2O2 and against H2O2-induced SIPS(stress-induced premature senescence), the study investigated the ability of againsting H2O2-induced SIPS and the changes of p21,CDK2 and cyclin E in human WI-38 cells treated with LTA.Methods1. The effects of LTA on the survival rate of human WI-38 cells in vitro were explored by MTT colorimetric. The effects of LTA on the rate of senescence in H2O2-induced SIPS human WI-38 cells were explored byβ-galactosidase(β-gal) cytochemistry staining.2. Changes of the mRNA expression of p21,CDK2 and cyclin E in human WI-38 cells treated with LTA were detected by RT-PCR; Changes of the protein expression of p21,CDK2 and cyclin E in human WI-38 cells treated with LTA were detected by Western blot.Results1. After treated with LTA of Bifidobacterium,the survival of WI-38 cells exposed to cytotoxic H2O2 were increased; Treatment with LTA(5,10μg/mL)led to a significant increase in the proportion ofβ-gal–positive cell.2. The mRNA and protein of p21 were decreased and the mRNA and protein of CDK2 and cyclin E in human WI-38 cells were increased after treated with LTA.Conclusions1. LTA of Bifidobacterium protects against cytotoxicity and premature senescence induced by H2O22. LTA can down regulate the mRNA and protein expression of p21 and up regulate the mRNA and protein expression of CDK2 and cyclin E in human WI-38 cells.